Socket Service

Environment Variables

• REDIS_URL: Redis connection URL (default: redis://localhost:6379).
• CLIENT_URL: Client URL for CORS (default: http://localhost:5173).

Channels

Redis Channels

• message: Used for broadcasting new messages.
• typing: Used for broadcasting typing status.

Class: SocketService

The core class managing WebSocket connections and Redis communication.

Constructor

constructor(httpServer: HttpServer)

• Initializes the Socket.IO server, Redis publisher/subscriber, and sets up event handlers.
• Parameters:
  • httpServer: An instance of Node.js HTTP server.

Methods

getUserStatus(userId: string): "online" | "offline"

• Retrieves the online status of a user.
• Parameters:
  • userId: ID of the user.
• Returns: User status (online or offline).

getOnlineUsers(): string[]

• Retrieves the list of online user IDs.
• Returns: Array of user IDs.

emitToUser(userId: string, event: string, data: any): void

• Emits a custom event to a specific user.
• Parameters:
  • userId: ID of the recipient user.
  • event: Event name.
  • data: Data to send.

Private Methods

setupRedisSubscribers(): void

• Subscribes to Redis channels and listens for messages.

setupSocketHandlers(): void

• Sets up Socket.IO event handlers for connection, disconnection, and custom events.

handleUserConnect(socketId: string, userId: string): void

• Manages user connection events, updates the online user list, and notifies clients.

handleUserDisconnect(socketId: string): void

• Handles user disconnection events and updates the online user list.

handleNewMessage(data: MessageData): Promise<void>

• Publishes a new message to Redis and the message queue.
• Parameters:
  • data: Object containing message details.

handleRedisMessage(data: MessageData): void

• Processes incoming messages from Redis and broadcasts them to relevant users.

handleTypingStatus(data: TypingData, isTyping: boolean): Promise<void>

• Publishes typing status to Redis.

handleRedisTyping(data: TypingData): void

• Processes incoming typing status from Redis and notifies clients.

Event Handlers

Client Events

• user:connect: Triggered when a user connects.

  • Payload: userId: string

• disconnect: Triggered when a user disconnects.

• message:new: Triggered when a new message is sent.

  • Payload:

    {
      chatId: string;
      content: string;
      sender: string;
      receiver: string;
      _id: string;
      isfile: boolean;
      createdAt: Date;
    }
    

• typing:start: Triggered when a user starts typing.

  • Payload:

    {
      chatId: string;
      userId: string;
    }
    

• typing:stop: Triggered when a user stops typing.

  • Payload:

    {
      chatId: string;
      userId: string;
    }
    

Server Events

• user:status: Notifies about a user's online/offline status.

  • Payload:

    {
      userId: string;
      status: "online" | "offline";
    }
    

• users:online: Sends the list of currently online users to the client.

• message: Broadcasts a new message to relevant users.

  • Payload:

    {
      message: MessageData;
      chatId: string;
    }
    

• typing:status: Notifies about typing status.

  • Payload:

    {
      chatId: string;
      userId: string;
      isTyping: boolean;
    }
    

Data Models

OnlineUser

interface OnlineUser {
  userId: string;
  socketId: string;
}

MessageData

interface MessageData {
  chatId: string;
  content: string;
  sender: string;
  receiver: string;
  _id: string;
  isfile: boolean;
  createdAt: Date;
}

TypingData

interface TypingData {
  chatId: string;
  userId: string;
}